This invention relates to gas turbine engines using radial turbines and centrifugal compressors in high pressure engine portion and arranged so as to achieve low fuel consumption.
Up till now the reduction in fuel consumption in smaller gas turbine engines has been limited by the difficulty in obtaining high pressure ratio, cooling small turbine components, and avoiding parasitic losses resulting from scaled down components, and by the high cost of miniature precision parts. Had it not been for the reasons given, small turbine engines would have seen an extended use generally, particularly because of the ability of such engines to operate with substantially lower emissions than gas engines, diesel engines and gasoline engines.
Many previous attempts have been made to solve the above problems, but the only other solution which addresses the situation uses a double entry first stage compressor in a single spool gas generator configuration. This configuration holds promise in the higher power range, but would be far too expensive for use in the lower power range, i.e. .ltoreq. about 1000 KW.